MIAMI — Their validation came in the form of another championship celebration that began here late Thursday night and probably won’t end for days. And as the final seconds ticked off the game clock inside AmericanAirlines Arena, LeBron James, Dwyane Wade and Chris Bosh reveled in the moment. They had earned it.

For Miami’s Big Three, the team’s 95-88 victory over San Antonio in Game 7 of the NBA Finals completed a journey several years in the making. Their Finals disappointment against Dallas in 2011, unforeseen setbacks and relentless criticism — much of it misguided — no longer mattered. James, Wade and Bosh accomplished what they set out to do: Win multiple NBA titles as teammates.

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That singular pursuit is what prompted the incomparable James — who led Miami with 37 points and 12 rebounds en route to his second NBA Finals MVP award — to walk away from the team that drafted him, incurring the wrath of fans in his home state. It’s why Wade, one of the game’s superstars, willingly stepped aside to let basketball’s best player lead the Heat. Bosh sacrificed the most. He went from being a franchise player to a third banana (albeit a good one).

The payoff was worth it. In winning consecutive NBA championships, Miami joined an exclusive club that includes Boston, Chicago, Detroit, Houston and the Los Angeles Lakers. The list of teams that have made at least three straight Finals appearances also is short: Boston, Chicago, Detroit, New York and the Lakers.

Since James, Wade and Bosh teamed up, Miami has achieved the type of success only attained by teams among the best of their eras. The hard work and mental toughness of the Big Three resulted in Miami earning a spot at the table. Call it Heat cred.

Winning at the highest level of competition is impressive in normal circumstances. There’s nothing normal about what James, Wade and Bosh have faced on their wild ride.

The all-stars broke new ground in free agency — and angered NBA owners — by signing with Miami to form a so-called super team. Heat President Pat Riley, who persuaded Wade to re-sign and successfully recruited James and Bosh, became a target of envious league decision-makers. But James, Wade and Bosh blocked out the noise.

As grown men and free agents, they had the right to determine where they would work. James, Wade and Bosh played by the NBA’s rules and took control of their careers when they could. Good for them.

Teams have most of the power in professional sports. They trade, decline to re-sign and release players. The Lakers have made an art form of acquiring other teams’ stars in an effort to extend their dynasty. Kareem Abdul-Jabbar, Shaquille O’Neal, Pau Gasol and Dwight Howard didn’t enter the league wearing purple and gold. It only seems that way.

Boston also went the superstar-quick-fix route. After the Celtics’ long Finals drought, they acquired Kevin Garnett and Ray Allen to team with Paul Pierce. That partnership produced five straight playoff berths, five division titles, three trips to the Eastern Conference finals, two NBA Finals appearances and one championship.

No one claimed the Celtics destroyed the integrity of the sport by constructing a top-heavy roster that featured three future Hall of Famers. It’s only cool if great teams are assembled through trades?

The “heat” James took was ridiculous. During his first seven seasons in Cleveland, James lifted the Cavaliers higher than they had ever been. It would have been a great story if the Akron, Ohio, native won a championship in the state in which he was born.

Cleveland management, however, failed to do its part. Antawn Jamison was the best player the Cavaliers got to play alongside James. Even Michael Jordan didn’t win a championship as a solo artist.

NBA old-timers mocked James for supposedly taking an easy path to trying to win titles. They said he would be Wade’s sidekick. Even if the Heat succeeded, according to James’s critics, James’s legacy would be tarnished because he needed the help of Wade and Bosh to win. What crazy thinking. And as it turned out, Wade needed James even more than James needed him.

Since winning the 2005-06 title, Miami had not advanced past the first round. The arrival of James and Bosh re-energized the franchise and helped the Heat overcome an unexpected problem: Wade’s knee pain.

The future Hall of Famer was selected all-NBA again this season. Wade had a 32-point performance in Game 4 of the Finals. Wade, though, struggled throughout the playoffs while receiving treatment on his sore left knee. Fortunately for the Heat, Wade succeeded in turning back the clock in the clincher, scoring 23 points and grabbing 10 rebounds in support of James.

Then there’s Bosh. A power forward who’s as his best shooting long jumpers, Bosh plays out of position at center in the Heat’s smaller lineup. He had a nightmarish experience against Indiana’s Roy Hibbert in the conference finals. For most of the Finals, Tim Duncan badly outplayed Bosh.

But Bosh came through with the rebound that set up Allen’s tying three-pointer at the end of regulation in Game 6. He blocked the Spurs’ last two shots to help preserve that victory. The Heat wouldn’t have gotten to Thursday night without Bosh.

Almost three years ago, three friends came up with a plan. It required them to come together, take on the rest of the NBA and build a championship legacy. Mission accomplished.

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